Process and composition for increasing the reactivity of sulfur scavenging oxides

ABSTRACT

In ridding fluids, including hydrocarbon fluids, both gaseous and liquid, of sulfur compounds including hydrogen sulfide, oxides of sulfur, and thiols, the present invention uses a small quantity of an activator, generally a noble metal oxide, preferably a copper species, along with a known oxide product, such as iron oxide or zinc oxide, to thoroughly remove sulfur contaminants in a short amount of time. The activator allows for the use of smaller reactor vessels and the production of hydrocarbon fluids substantially free of sulfur products.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/024,239 filed Aug. 20, 1996 and is a continuation-inpart of co-pending U.S. patent application Ser. No. 08/757,228, filedNov. 27, 1996.

FIELD OF THE INVENTION

[0002] This invention relates to the activation of oxide products thatare reactant with sulfur compounds, wherein the activated oxide productssweeten fluids, both gases and liquids, polluted with sulfur-bearingcompounds such as hydrogen sulfide and thiols (mercaptans). Preferably,this invention relates to improving the removal of sulfur compounds fromhydrocarbon streams by adding an activator to an iron oxide productwhich increases the rate of reactivity of the iron oxide product withthe sulfur compounds found in hydrocarbon streams.

BACKGROUND OF THE INVENTION

[0003] Oxides, particularly iron oxides, supported on inert particulatematter have long been used in flow-through packed-bed processes to reactwith and scavenge hydrogen sulfide and thiols (mercaptans) present innatural gases and liquid hydrocarbons. The reactions between oxides andsulfides traditionally have been relatively slow, as compared to othersulfur removal or gas sweetening systems. Because of the slow rate ofreaction, large iron oxide beds contained in large reactor vessels havebeen required in order to adequately remove hydrogen sulfide and thiolsfrom the hydrocarbon fluids. The larger reaction vessels allow forlonger contact times between the oxides and the sulfur compounds, withthe longer contact times being necessary to adequately remove the sulfurcompounds. A somewhat offsetting advantage to the slowness and sizerequirements of the iron oxide beds is that the reacted iron oxide bedmaterial may be disposed of as non-toxic waste, unlike some other sulfurremoval processes which require toxic waste disposal systems.

[0004] Current iron oxide based products designed to remove sulfurcompounds from gas or vapor streams have performance limitations. Anexample of such a performance limitation relates to the minimumhydrocarbon fluid or gas residence time in a reactor vessel, as theresidence time required for the gas in the vessel limits the space andpractical vessel size in some cases. Minimum gas exposure or retentiontime in low pressure iron oxide beds typically ranges between about 1 toabout 1.3 minutes based on the amount of unoccupied bed space and actualgas volume. Thus, large diameter vessels and beds are typically requiredfor efficient design common in low pressure iron oxide bed applications.Large diameter vessels are also required in high pressure oxideprocesses, and, like low pressure iron oxide beds, are very expensive.Because of the lengthy gas retention time, it is difficult to fit vesselsizes into “small foot print” applications like offshore drilling orlimited space plant facilities. Consequently, a problem exists becausesmall vessel sizes cannot be used to sweeten hydrocarbon fluids, meaningcertain facilities do not have access to packed bed iron oxideprocesses. Because of the space limitation, it would be desirable tohave an iron oxide bed that required less space, preferably about halfof the cross sectional area normally required, and was still capable ofsweetening hydrocarbon fluids.

[0005] Unplanned increases in gas volumes and inlet hydrogen sulfidelevels, beyond the design capacity of normal iron oxide beds, causeunder-utilization of the iron oxide product and excessive costs. Ironoxide systems that are properly designed initially can experienceincreased gas flow and/or higher levels of hydrogen sulfide thatsignificantly exceed normal design conditions resulting in inefficientutilization of iron oxide type products and substantially higheroperating costs. Because unplanned increases in volume frequently occur,it is desirable to have a product and process that can handle increasesin volume without wasting the iron oxide product.

[0006] An additional problem involves hydrocarbon fluids, gas andliquid, that are less than totally water saturated, as the unsaturatedhydrocarbon fluids require long contact times to effectively removehydrogen sulfide. Also, systems designed for water saturated conditionsoperate inefficiently when the fluid is not water saturated. Natural gasand vapor, and liquid hydrocarbon streams that are less than totallywater saturated will result in the decreased removal efficiency ofhydrogen sulfide by the iron oxide product and higher operating costs.Thus, a problem exists because current iron oxide products arecommercially efficient only in the removal of dissolved hydrogen sulfideor other sulfur compounds in hydrocarbon fluids if there is sufficientcontact time and the hydrocarbon fluids are saturated. Often, however,it is not practical to inject water to fully saturate the hydrocarbonfluid to achieve normal hydrogen sulfide removal. Consequently, it isdesirable to have a system for sweetening hydrocarbon fluids that doesnot require the hydrocarbon fluids to be totally water saturated.

[0007] Systems designed to control odors in vapors from wastewater andoil tanker vent scrubber systems often utilize blowers and pressureboosters that create unsaturated gas or vapor streams by changing thephysical properties of the hydrocarbon fluids. These operationalpractices can reduce the efficiency of iron oxide products in removinghydrogen sulfide and other sulfur compounds from fluids. Thus, it isdesirable to have a system that can remove hydrogen sulfide and othersulfur compounds from gas and vapor streams that have constantlychanging physical properties.

[0008] Additionally, some systems may inject air into the hydrocarbonfluid. The injection of air, which includes oxygen, causes increasedcorrosion and safety concerns despite increased capacity for hydrogensulfide removal. The intentional and unintentional inclusion of air,including oxygen, in natural gas or vapor streams has long been seen toincrease the capacity of iron oxide impregnated wood chips and otheroxide products to react with hydrogen sulfide. However, corrosion andsafety concerns are greatly increased due to the presence of oxygen,which will react with the vessel containing the oxide product. Also,many natural gas contracts presently specifically limit the amount ofoxygen in the gas and some contracts prohibit the intentional injectionof air due to problems caused downstream in gas transportation systems.The inclusion of a “non-oxidizer” stimulant or activator in the ironoxide product that enhances the capacity of sulfur removal, without theassociated problems of organic and inorganic oxidizers, like air, wouldenhance the use of oxide products in sulfur removal processes.

[0009] Liquid hydrocarbons commonly include dissolved hydrogen sulfideand other sulfur compounds. In some cases, the hydrogen sulfide removalsufficiently meets the required product quality for sales to pipelinesand transporters. Frequently, however, other sulfur compounds, such asmercaptans, carbonyl sulfides, and carbon disulfide need to be removedto meet required sulfur limits and product quality tests before thehydrocarbons can be sold. An improved iron oxide product that wouldefficiently remove hydrogen sulfide and other sulfur compounds to meetrequired sulfur limitations in hydrocarbon fluids would significantlyincrease the commercial utility of iron oxide sulfur removal processes.

[0010] Thus, it is desirable to have an iron oxide bed process andcomposition that functions in a small reactor vessel, removes sulfurcompounds in a short amount of time, removes sulfur compounds fromunsaturated fluids, does not require the injection of air, and removesmost if not all of the sulfur compounds in a fluid, particularly ahydrocarbon fluid. As will be seen, the present invention activates theoxide bed process and composition to meet the above listed criteria.

SUMMARY OF THE INVENTION

[0011] The present invention relates to the use of an activator in anoxide product reactant with sulfur compounds. The activator increasesthe rate of reactivity of the oxide product with sulfur compoundscontained in fluids. Preferably, the activator will have a higherelectro-potential than the oxide product so that when the activator iscoupled with the oxide product the coupling will result in an increasein the reactivity of the oxide product with sulfur compounds containedin fluids. Importantly, the activator increases the rate of reactivityof the oxide product without requiring high temperatures to helpincrease the rate of reactivity or the addition of air, oxygen inparticular. The activator causes increased reactivity at a temperatureequal to or less than 300° C. Additionally, when the oxide product andthe activator are coupled, the oxide product can remove sulfurcompounds, including oxides of sulfur, hydrogen sulfide, and thiols,from fluids including saturated and unsaturated fluids, as well as,liquid, gas, or a combination thereof, and not just hydrocarbon fluids.

[0012] Typically, the activator is a noble metal oxide and the oxideproduct is an iron oxide or zinc oxide product. Noble metals are metalswhich are not very reactive, such as silver, gold, and copper. One ofthe most preferred embodiments of the activator involves the use ofsmall amounts of copper, including copper metal and copper oxide, eithercuprous and/or cupric, added to a conventionally-made sulfide reactantoxide-bed, such as an iron oxide bed. An example of such an iron oxidebed used for hydrogen sulfide removal is found in U.S. Pat. No.5,320,992. The copper activator reacts with the iron oxide product inthe iron oxide bed to increase the rate of reactivity of the iron oxideproduct with sulfur compounds found in fluids, including hydrocarbonfluids. The increased reactivity of the iron oxide product caused by thecopper activator results in the completion of the sulfur compoundremoval reaction in less than half the time of a normal sulfur removalreaction, making feasible the use of iron oxide beds equal to half, orless, the volume than conventional beds. This unexpected result isbelieved to be due to the substantially higher electro-potential of thecopper as compared to the iron oxides. Additionally, the use of limitedamounts of copper activator will prevent the exhausted bed from beingrated as a hazardous waste by the current standards promulgated by theEnvironmental Protection Agency.

[0013] Metal oxides, such as iron and zinc oxide, have anelectronegative potential, meaning the potential is on the active oranodic end of the Emf series, with the active end relating to metalswhich tend to corrode. Noble metals, copper for example, have anelectropositive potential, meaning the potential is on the noble orcathodic end of the Emf series. Cathodic metals do not readily corrode.The Emf series is a listing of elements according to their standardelectrode potential. When two dissimilar metals, a noble metal and anactive metal, are combined a galvanic cell is formed, which will resultin galvanic corrosion. Corrosion of a metal is increased because of thecurrent caused in a galvanic cell, so that as the corrosion rate isincreased so is the reactivity of the metal. In particular, when copper,for example, is added to iron oxide, for example, a galvanic cell isformed which causes the iron oxide to corrode faster and thus be morereactive with various sulfur species. What this means is that increasingthe electro-potential relates to forming a galvonic cell so thatcorrosion is increased and reactivity with various sulfur species isincreased. Most of this information, as well as, the Emf series werediscussed and disclosed in the “Basic Corrosion Course” offered by theNational Association of Corrosion Engineers in October of 1978.

[0014] According to another aspect of the present invention, even whenthe hydrogen sulfide-tainted fluids include thiols, mercaptans inparticular, offensive odors are completely eliminated along with areduction of total sulfur content to levels acceptable to commercialpurchasers. Another aspect of the invention is that hydrocarbon fluidsdo not have to be saturated in order to have the oxide product, coupledwith an activator, adequately remove thiols (mercaptans).

[0015] Because the inventive activator effectively raises the rate ofreactivity of oxide products, this invention results in the improvementin the use of disposable oxide products for the removal of sulfurcompounds from natural gas and vapors, and other hydrocarbon liquids.Thus, the present invention is desirable because it allows for an oxideproduct that can be contained in a small reactor vessel, results in theremoval of sulfur compounds in a short amount of time, the removal ofsulfur compounds from unsaturated hydrocarbon fluids, the non-inclusionair, and the thorough removal of the sulfur compounds from fluids.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is an X-ray diffraction reading showing the presence ofcopper oxide after having hydrogen sulfide pass through an iron oxideproduct.

DESCRIPTION OF THE INVENTION

[0017] In accordance with the present invention an activation method andcomposition are provided for increasing the reactivity of oxideproducts, preferably iron oxide or zinc oxide products, with sulfurcompounds in contaminated fluids, including gas, liquid, or acombination thereof, resulting in the removal of the sulfur compoundsfrom the fluids. The oxide products that react with sulfur compounds arealso know as sulfide reactant oxides. The process is initiated by addingan activator composition, preferably a noble metal oxide, to the ironoxide product, preferably a packed-bed iron oxide product. The noblemetal oxide activator will react with the iron oxide product to increasethe reactivity of the iron oxide product with sulfur compounds. Thereaction between the activator and iron oxide product causes the ironoxide product to more readily react with sulfur compounds, such asthiols, oxides of sulfur, and hydrogen sulfide (H₂S), resulting in theremoval of the sulfur compounds from various fluids. Preferably, thesulfur compounds are removed from the hydrocarbon fluids so that uponremoval of the sulfur compounds the hydrocarbon fluids can be used forcommercial purposes.

[0018] The process, as stated, involves adding an activator to an ironoxide or zinc oxide product reactant with sulfur compounds, with theactivator reacting with and activating the iron oxide product. Theactivator increases the reactivity of the iron oxide product with sulfurcompounds which can be found in hydrocarbon fluids. The activator may beselected from the noble metal oxides, which includes, but is not limitedto, platinum oxide, gold oxide, silver oxide, copper oxide, cadmiumoxide, nickel oxide, palladium oxide, lead oxide, mercury oxide, tinoxide, and cobalt oxide. In addition to the noble metal oxides, alloysmade of noble metals and some metals may also be used. The mostpreferred noble metal oxide, is copper oxide, either cuprous or cupricoxide. Also, a combination of cuprous and cupric oxide may be used. Notonly may copper oxide be used; but copper metal is also suitable foruse. In general, any copper species can be used as an activatorincluding copper oxides, copper alloys, copper carbonate, and coppermetal. Regardless of the noble metal oxide selected, the activator isdesigned to increase the efficiency of treatment of fluids with knowniron oxide or zinc oxide products. The activator will generally be of apowder grade particle size; however, the activator can have a particlesize ranging between a U.S. mesh size 8 and a U.S. mesh size 325.

[0019] The activator causes increased reactivity in the iron oxide orzinc oxide product, referred to generally throughout as the iron oxideproduct, because it has a higher electro-potential than the iron oxideproduct, with the dissimilar electro-potential causing bi-metalliccoupling between the activator, copper oxide for example, and the ironoxide product. This bi-metallic coupling results in an increased rate ofreaction between the iron oxide product and the sulfur compounds foundin fluids, in particular hydrocarbon fluids. The activator causes theiron oxide to be more reactive by increasing the corrosion rate of theiron oxide, which causes an increased reactivity between the iron oxideproduct and sulfur compounds. Essentially, the activator causes the ironoxide to react with the sulfur compounds before the activator reactswith the sulfur compounds. More specifically, while copper oxide isknown to react quickly with hydrogen sulfide, the reaction between thecopper oxide and the hydrogen sulfide essentially takes place after thereaction of the activated iron oxide with the hydrogen sulfide, with thereaction between the copper oxide and the hydrogen sulfide continuinglonger than the concentration of the activator accounts for. This isdemonstrated in FIG. 1, which show the presence of copper oxide in aniron oxide bed after having sulfur compounds pass through and react withthe iron oxide bed. The presence of copper oxide is shown in FIG. 1 byline 6, with FIG. 1 being an X-ray diffraction reading taken after theactivated iron oxide product had removed hydrogen sulfide fromhydrocarbon gas. In particular, FIG. 1 shows that the copper oxideactivated the iron oxide to react first, as the amount of hydrogensulfide that was passed through the iron oxide bed was equal to eight(8) times more hydrogen sulfide than would be necessary to exhaust thecopper oxide present in the iron oxide bed. Because the copper oxide didnot completely react with the hydrogen sulfide this indicates that theiron oxide reacted with the hydrogen sulfide before the copper oxide. Inaddition to coupling with and activating iron oxides, the activator canbe used to activate other oxides. The other oxides, besides iron oxide,are oxides having a lower electro-potential than the activator.

[0020] An amount of activator equal to less than 1% by total weight ofthe iron oxide product is sufficient to increase the reactivity of theiron oxide product with the sulfur species. Thus, the addition of asmall amount of the activator, such as copper oxide, in combination withan iron oxide product results in a faster reaction with hydrogensulfide, thiols (mercaptans), and other sulfur compounds, includingcarbonyl sulfide and carbon disulfides. In addition to increasing thereactivity of the iron oxide product, the copper oxides are preferredbecause they are readily available and meet current environmentalstandards as promulgated by the Environmental Protection Agency.Finally, dependence upon fully water saturated gas or vapor streams forefficient sulfur removal is not necessary due to the higher reactionrates caused by the activator of this invention.

[0021] Use of copper oxide as an activator is also desirable because itgenerally does not corrode the reactor vessel. When unprotected mildsteel equipment, such as the reactor vessel that houses the iron oxidebeds, is exposed to copper ions corrosion of the steel can result.However, because a relatively small amount of noble metal oxide,preferably copper oxide, is used, the reactor vessel is notsignificantly corroded. Reactor vessel corrosion rates are notsignificantly higher than current iron oxide products due to the minimalpresence of copper ions that cause high corrosion rates.

[0022] The oxide product that reacts with sulfur is also known assulfide reactant oxide and is selected from a metal oxide group having alower electro-potential then the activator. Typically, the oxide productis an iron oxide product of the formula Fe_(x)O_(y), with “x” equal tobetween 1 and 3, and “y” equal to between 1 and 4. Also, hydroxides ofiron oxides may be used. More particularly, the iron oxide is preferablyeither Fe₂O₃, Fe₃O₄, or a combination thereof. An alternative to theiron oxide product is a zinc oxide product. Normally, the iron oxideproduct is combined with an inert bed material to form an iron oxide bedthat is housed in a reactor vessel; but, it is not necessary to combinethe iron oxide product with a bed material, inert or otherwise. When theiron oxide bed is made of an inert carrier material, the iron oxideproduct attaches to the inert carrier material which holds the ironoxide product in place when contacted with hydrocarbon fluids.Preferably, the inert carrier is a calcinated montmorillonite carrierwhich is desirable because it is non-hazardous, stable, reliable, andeasy to clean. Instead of an inert carrier the iron oxide product can becombined with other carriers such as water. Once the iron oxide productand carrier have been reacted with sulfur compounds, the reactant ironoxide product remains stable and non-hazardous according to currentlypromulgated Environmental Protection Agency and state standards.

[0023] When activated, the iron oxide product reacts with sulfurcompounds to remove the sulfur compounds from fluids, including gases,liquids, vapors, and combinations thereof as well as non-fully saturatedfluids. The activated iron oxide product can remove sulfur compoundsfrom fluids including air streams, carbon dioxide streams, nitrogen gas,and hydrocarbon gases, liquids, and combinations thereof. The sulfurcompounds that are removed from the fluids include, but are not limitedto, C₁ to C₃ thiols (mercaptans), hydrogen sulfide, carbon disulfides,carbonyl sulfide, and other oxides of sulfur.

[0024] The preferred iron oxide bed composition containing the activatoris comprised of a carrier equal to from about 0% to about 95% by weightof the total iron oxide bed composition, more preferably from 0% toabout 77% by weight, and even more preferably from about 59% to about76.8% by weight. An amount of iron oxide product is added to the ironoxide bed composition equal to from about 3% to about 30% by weight ofthe total iron oxide bed composition, and more preferably equal to fromabout 5% to about 22% by weioht of the total iron oxide bed composition.An amount of water can be added to the iron oxide bed compositionranging from approximately 0% to approximately 80% by weight of thetotal iron oxide bed composition and more preferably approximately 18%by weight of the total iron oxide bed composition. Finally, anactivator, preferably copper oxide, is added to the iron oxide bedcomposition in an amount equal to from about 0.125% to about 5% byweight of the total iron oxide bed composition. Preferably, theactivator is used in an amount equal to from about 0.25% to about 2% byweight of the total iron oxide bed composition. Larger amounts of theactivator, greater than 5% by weight, can be used; however, it is mostpreferred to use an amount of activator equal to approximately 1% byweight of the total iron oxide bed composition. Further, the reactor bedwill preferably be maintained at a temperature equal to or less than300° C.

[0025] An alternative embodiment would include an amount of iron oxideproduct equal to from about 95% to about 99.875% by weight of the totaliron oxide bed composition in combination with an amount of activatorequal to from about 0.125% to about 2% by weight of the total iron oxidebed composition.

[0026] Another embodiment would include the use of water as the primarycarrier, with the water added in an amount equal to from about 50% toabout 80% by weight of the total iron oxide bed composition, an amountof iron oxide product added to the water in an amount equal to fromabout 5% to about 22% by weight of the iron oxide bed composition, andan activator added to the water and iron oxide product equal to fromabout 0.125% to about 5% by weight of the total iron oxide bedcomposition. The preferred combination of activator to iron oxideproduct is equal to about 1 part by weight of activator to about 10 toabout 50 parts by weight of iron oxide product. It should be noted thatthe amount of activator required is comparatively small when analyzed inview of the oxide product. This is because it takes a comparativelysmall amount of activator to increase the reactivity of the iron oxideproduct, or other oxide products.

[0027] It should be further noted that the presence of oxygen in thefluid containing sulfur compounds further increases theelectro-potential differential between the oxide product and theactivator. Thus, even smaller vessels with dramatically shorter contacttimes are possible for order control applications and hydrogen sulfideremoval systems with vapors naturally containing, or with the deliberateaddition of, air, which may include oxygen.

[0028] In order to further illustrate the present invention, thefollowing examples are given. However, it is to be understood that theexamples are for illustrative purposes only and are not to be construedas limiting the scope of the subject invention.

EXAMPLES Example 1

[0029] As will be shown in the following example, smaller-sized reactorvessels can be used for hydrogen sulfide and other sulfur speciesremoval, including thiols (mercaptans), from gaseous and liquidhydrocarbons by adding a small amount of copper oxide activator to aniron oxide based reaction bed contained in a steel reactor vessel.

[0030] Hydrocarbon gas samples were filtered in a reactor vessel whichwas 8 feet in length and had a diameter of 2 inches. The vesselcontained 10 pounds of an experimental iron oxide mix, which containedabout 5.921 pounds of an inert carrier, with the carrier being acalcinated montmorillonite carrier, an amount of iron oxide powder equalto approximately 2.15 pounds, and an amount of water equal toapproximately 1.9 pounds. Five (5) batches were made of the iron oxidemix, so that five (5) different tests could be conducted in the reactorvessel. Each of the five tests were initiated by passing nitrogen/carbondioxide gas contaminated with hydrogen sulfide, the amount of hydrogensulfide contained in contaminated gas is listed below, through the ironoxide mix contained in the reactor vessel. In three of the tests copperoxide was added to the iron oxide mix, the amount of which is listedbelow. In two of the tests no copper oxide was added to the iron oxidemix. Also, the tests were conducted on different amounts of hydrogensulfide (H₂S) contaminant contained in nitrogen/carbon dioxide gas.Additionally, some nitrogen/carbon dioxide gas samples contained oxygen,the amount of which is listed below. Thus, the nitrogen/carbon dioxidesamples that were tested, included samples with oxygen and withoutoxygen.

[0031] The amount of copper oxide activator added the iron oxide bed wasequal to about 1% or less by weight of the total bed composition. Theactual amount of copper oxide added was about 1% by weight or an amountequal to about 0.1 pounds and about 0.25% by weight or about 0.025pounds. The specific parameters for each test are listed in the tablebelow. The conditions in the reactor vessel in which the tests wereconducted are as follows: Test Conditions: Temp 70° F. Flow Rate ofNatural Gas containing H₂S 5.41 liters/min. Pressure 0.5 psig. BedHeight 7.9 ft. Gas was water saturated

[0032] Contact time for the gas in the test unit was about 50 seconds atthe above listed pressure, temperature, and flow rate. The gas wasfiltered through the reactor vessel containing the iron oxide mix. Ascan be seen below, a comparison was made between the efficiency ofremoval of the iron oxide mix without an activator and the iron oxidemix with an activator, copper oxide. The tests were also broken intonigrogen/carbon dioxide gas samples containing moderate amounts andextreme amounts of H₂S. The extreme H₂S contaminated nitrogen/carbondioxide gas was filtered through an iron oxide mix without an activator,an iron oxide mix containing 1.0% by weight of activator, and an ironoxide mix containing 0.25% by weight of an activator. Moderate H₂SContamination Extreme H₂S Contamination Gas H₂S 500 ppm in N₂ H₂S 2200ppm in N₂ Composition No Oxygen Oxygen  4% by volume Carbon Dioxide 14%by volume Carbon Dioxide 14% by volume Test Results Iron  1% by wt. IronCopper Oxide Oxide Only Copper Oxide Oxide Only 1.0% by wt 0.25% by wtBed Depth Greater Than Less Than Greater Than Less Than Less Than forComplete 7.9 feet 4.7 feet 7.9 feet 2.7 feet 3.7 feet H₂S Removal

[0033] Measurements were taken by Sensidyne hydrogen sulfide and totalmercaptan stain tubes manufactured by the Sensidyne company.

[0034] As can be seen, in the moderately contaminated gas the additionof a small amount of activator, copper oxide, substantially decreasedthe iron oxide bed depth required for complete hydrogen sulfide removal.The iron oxide bed with an activator required 3.2 fewer feet to removethe sulfur compounds than the iron oxide bed without an activator. Inthe extreme contaminated gas, the activated iron oxide bed required lessthan half the amount of material, 3.7 feet as compared to 7.9 feet, toremove the sulfur compounds. Furthermore, as can be seen, an increasedamount of activator increases the reactivity of the iron oxide. The ironoxide mix having 1% by weight of an activator added thereto onlyrequired 2.7 feet to remove the hydrogen sulfide; whereas, the ironoxide mix containing 0.25% by weight of an activator added theretorequired less then 3.7 feet to remove the hydrogen sulfide. A lesseramount of iron oxide mix was required to remove the hydrogen sulfidefrom gas extremely contaminated with H₂S as compared to gas moderatelycontaminated with H₂S. The reason there was better removal in the gaswith extreme hydrogen sulfide contamination, as compared to the gas withmoderate hydrogen sulfide contamination, was the addition of oxygen tothe gas. This shows that oxygen further increases the reactivity of theiron oxide product when an activator is added thereto. It should bepointed out that the addition of the oxygen did not increase thereactivity of the iron oxide product without an activator.

[0035] Thus, the above examples demonstrate that the use of an activatorresults in the ability to use a smaller bed and vessel. The examplesalso demonstrate that the iron oxide product has increased activity whenexposed to an amount of oxygen in combination with an activator.

Example 2

[0036] The following experiment was conducted to determine the amount ofdissolved hydrogen sulfide and mercaptans removed from natural gasliquids (NGL) by an iron oxide product composition containing anactivator. The removal of hydrogen sulfide and mercaptans from naturalgas liquids is indicated by the reduction of the hydrogen sulfide andmercaptan concentrations measured in the vapor or “headspace” adjacentto the liquid.

[0037] Two tests were conducted in two (2) reactor vessels that were 4feet high. For each test each reactor vessel contained approximately 40pounds of reaction material, including about 23.684 pounds of solidinert carrier, a montmorillonite carrier, about 7.6 pounds of water, andabout 8.6 pounds of iron oxide powder. In one test approximately 0.4pounds of copper oxide was added to the reaction material, while theother test did not have any copper oxide added to the reaction material.

[0038] The tests conditions were as follows:

[0039] Natural Gas Liquids (NGL) 72 API (density) at 70° F.

[0040] Headspace H₂S Untreated=>4,000 ppm.

[0041] Headspace Mercaptans Untreated—The mercaptan content could not bedetermined due to high H₂S levels.

[0042] Flow Rate set at 2″ equivalent unoccupied bed rising velocity.

[0043] Measurements were taken by Sensidyne hydrogen sulfide and totalmercaptan stain tubes manufactured by the Sensidyne company.

[0044] Test results, as indicated by headspace concentrationmeasurements, were as follows: Iron Oxide Iron Oxide With 1% by wt.Copper Oxide Only At 4 ft. level At 8 ft. level Hours In At 4 ft. levelTotal Total Test H₂S H₂S Mercaptans H₂S Mercaptans At Start 400 ppm* 0ppm  0 ppm 0 ppm 0 ppm  6 Hr. * 0 ppm 35 ppm 0 ppm 0 ppm of Flow 21Hr. * 0 ppm 40 ppm** 0 ppm 0 ppm of Flow

[0045] unit(s) loaded with the copper oxide activator and the iron oxideproduct without the need for further processing. Conversely, the ironoxide product that did not have an activator did not result insufficient removal of the hydrogen sulfide or mercaptans. Additionally,it should be pointed out that the iron oxide bed at the 8 foot level didnot contain any detectable sulfur compounds. This means that the sulfurcompounds were removed from the hydrocarbon fluid prior to contactingthe iron oxide product at the 8 foot level.

[0046] Accordingly, use of the present invention affords at least thesesignificant advantages: increased speed of reactivity permits the use ofmuch smaller beds of reactive materials; and, when mercaptans and/orhydrogen sulfide are present in liquid hydrocarbons, the products of thereaction are odor-free and are no longer contaminated with these sulfurcompounds.

Example 3

[0047] Two reactor vessels were prepared that was 15 feet in length andeach reactor vessel contained approximately 30 pounds of iron oxide mix.The iron oxide mix contained about 17.763 pounds of carrier, about 5.7pounds of water, about 6.45 pounds of iron oxide product, and about0.087 pounds of copper oxide. The reactor vessel was connected to acarbon dioxide gas source. The carbon dioxide gas, before passage intothe reactor, was water saturated through a bubbler and filtered in thereactor under the following conditions: Flow Rate (ft³/hr) 30Temperature (° F.) 70 Pressure (psig) 400 Bed Height (ft.) 30 Inlet H₂S(ppm) 25 Inlet Mercaptans (ppm) 20

[0048] The inlet gas contained a number of other sulfur species, inaddition to mercaptans and hydrogen sulfide, the most abundant sulfurcompounds being methyl and ethyl sulfides and disulfides. Three carbondioxide gas samples were tested, one sample per day for threeconsecutive days, with each sample passing through the iron oxide mix inthe same reactor. The sulfur components, other than hydrogen sulfide andmercaptans, were not removed by the iron oxide mix. The hydrogen sulfide(H₂S) and Mercaptans were removed by about 5 ft. of the iron oxide mix,out of a possible 30 feet. The following table shows the amount ofhydrogen sulfide and mercaptans entering the reactor as well as theconditions in the reactor vessel. The following table shows the datathat was collected and formulated with measurements taken by Sensidynehydrogen sulfide and total mercaptan stain tubes manufactured by theSensidyne company and test trailer meters. Sample 1 Sample 2 Sample 3Inlet H₂S (ppm) 25 22 24 Inlet Mercaptans (ppm) 20 20 20 First Port H₂S(ppm) 0 0 0 First Port Mercaptans (ppm) 0 0.5 0.75 Column 1 temp (° F.)85 68 84 Column 1 press (psig) 410 410 400 Flow (ft³/hr.), actual 30 3030

[0049] The tested samples revealed that the activated iron oxide mixremoved the contaminants with 5 feet of iron oxide mix from thecontaminated carbon dioxide streams. Specifically, it should be notedthat no contaminants were detected at the second port or 10 foot mark.The tests showed that no hydrogen sulfide (H₂S) or mercaptans passed thefirst 15 feet of the reactor. Thus, the iron oxide mix with an activatorwas able to remove hydrogen sulfide and mercaptans from water saturatedcarbon dioxide streams.

Example 4

[0050] Two reactor vessels were prepared that were each 15 feet inlength and each reactor vessel contained approximately 30 pounds of ironoxide mix. The iron oxide mix contained about 17.763 pounds of carrier,about 5.7 pounds of water, about 6.45 pounds of iron oxide product, andabout 0.087 pounds of copper oxide. The reactor vessel was connected toa carbon dioxide gas well. The carbon dioxide gas was 20% watersaturated and was run in the reactor under the following conditions:Flow Rate (ft³/hr) 30 Temperature (° F.) 70 Pressure (psig) 400 BedHeight (ft.) 32 Inlet H₂S (ppm) 25 Inlet Mercaptans (ppm) 20 InletCarbonyl Sulfide (ppm) .025

[0051] The inlet gas contained a number of other sulfur species, inaddition to mercaptans, hydrogen sulfide, and carbonyl sulfide, the mostabundant sulfur compounds being methyl and ethyl sulfides anddisulfides. Three carbon dioxide gas samples were tested, one sampletested per day for three consecutive days, with each sample passingthrough the iron oxide mix in the same reactor. Hydrogen sulfide andmercaptans were tested for, in addition to carbonyl sulfide. Othersulfur compounds were not removed by the iron oxide mix, nor were theytested for. The following table shows the amount of hydrogen sulfide,mercaptans, and carbonyl sulfide entering the reactor as well as theconditions in the reactor vessel. The following table shows the datathat was collected and formulated with measurements taken by Sensidynehydrogen sulfide and total mercaptan stain tubes manufactured by theSensidyne company and test trailer meters. Sample 1 Sample 2 Sample 3Inlet H₂S (ppm) 25 22 24 Inlet Mercaptans (ppm) 20 20 20 Inlet CarbonylSulfide 0.025 0.025 0.025 First port H₂S (ppm) 0 Broke through Brokethrough port 3 (15 ft) port 3 (15 ft) First port Mercaptans (ppm) 0Broke through Broke through port 3 (15 ft) port 3 (15 ft) First portCarbonyl sulfide 0 Broke through Broke through port 2 (10 ft) port 3 (15ft) Column 1 temp (° F.) 54 Column 1 press (psig.) 410 Flow (ft³/hr),actual 30

[0052] As can be seen, the activated iron oxide product did not removethe sulfur compounds from the water unsaturated carbon dioxide gas aseffectively as it did the sulfur compounds from the water saturatedcarbon dioxide gas. But, the activated iron oxide product still removedsulfur compounds from the unsaturated carbon dioxide gas.

Example 5

[0053] To test whether copper metal powder and copper oxide increase thereactivity of iron oxide with sulfur compounds three (3) towers were setup in a side-by-side arrangement. The three (3) towers were each six (6)inches in diameter and five (5) feet tall and contained approximately 70pounds of material reactive with sulfur compounds. The three (3) towerseach had an inlet where jet fuel entered the towers. The jet fuel passedinto the towers from a common source. An amount of jet fuel streamcontaminated with 126 parts per million by weight of mercaptans waspassed through each of the reactor towers, so that three (3) separatestreams of jet fuel, in an amount equal to 400 milliliters per minute,was passed through each of the three (3) reactor towers. The jet fuelpassed through the reactor towers under atmospheric pressure and atemperature of 80° F. After passage through the reactor towers it wasdetermined at the outlet how much of the mercaptans remained in the jetfuel after passage through the three (3) different reactor towers. Themercaptan levels were determined 48 hours after initiation of the tests,so that the jet fuel passed through the reactor vessels for 48 hourswith a reading then taken at the 48 hour mark.

[0054] Reactor No. 1, which was non-activated material, contained 70pounds of material comprised of 59% by weight montmorillonite, an amountof iron oxide (Fe₂O₃) equal to 21.75% by weight, and an amount of waterequal to 19.25% by weight. At the end of 48 hours it was found that thejet fuel contained an amount of mercaptans equal to 78 parts per millionby weight, meaning approximately 48 ppm by weight had been removed bythe non-activated material.

[0055] In the second reactor, the clay or montmorillonite, and waterwere added in the same amount as in the first reactor and the iron oxidewas added in an amount equal to 21.25%. Additionally, an amount ofcopper powder was added in an amount equal to 0.5% by weight of thereactor materials. It was found that after 48 hours the jet fuelcontained approximately 15.8 parts per million by weight of mercaptansafter passage through the iron oxide activated with copper powder.

[0056] In a third reactor, the reactor contents were prepared the sameas in the reactor containing the copper metal powder, however, an amountof copper oxide equal to the same amount of copper powder was addedthereto. As such, the copper oxide was added in an amount equal to 0.5%by weight of the contents of the reactor. The mercaptans in the jet fuelwere measured after passage through the reactor contents and at the endof 48 hours. It was found that 8.5 parts per million by weight ofmercaptans remained in the jet fuel after passage through the iron oxideactivated with copper oxide.

[0057] As can be seen, both the copper metal and the copper oxideprovided for suitable removal of sulfur compounds and in particularmercaptans from the hydrocarbon stream.

Example 6

[0058] A test was conducted to show that zinc oxide could be activatedto more readily remove sulfur compounds from fluids than non-activatedzinc oxide. As such, two (2) side-by-side tests were conducted tocompare activated zinc oxide with non-activated zinc oxide.

[0059] The activated zinc oxide was formed by mixing 240 grams of inertbase, with 80 grams of water, 77 grams of zinc oxide, and 3 grams ofcupric oxide. The total weight of the mixture was 400 grams. Afterformation, the activated zinc oxide was placed in a test reactor havinga one (1) inch diameter and a twelve (12) inch length. The activatedzinc oxide was placed in the reactor at a depth of 10.5 inches.

[0060] A non-activated zinc oxide composition was formed by mixing 240grams of inert base with 80 grams of water and 80 grams of zinc oxide.Again the total weight of the mixture was 400 grams. The non-activatedzinc oxide mixture was then placed in a test reactor having the samedimensions as the test reactor used for the activated zinc oxide, withthe non-activated zinc oxide present in the same depth as the activatedzinc oxide.

[0061] Each of the reactors had an amount of water saturated nitrogencontaining 3000 ppm of hydrogen sulfide passed therethrough. Thenitrogen gas had a flow rate of 3000 m/min, through each of the reactorvessels and the reactor vessels were each at a temperature of 80 F and apressure of 3 psig. The nitrogen gas was passed through each of the zincoxide compositions in the reactor vessels for three (3) hours. At theend of the three (3) hours the amount of hydrogen sulfide in thenitrogen gas was measured, at the outlet of non-activated zinc oxidereactor vessel 525 ppm of hydrogen sulfide was measured in the treatednitrogen gas. At the outlet of the activated zinc oxide reactor vessel 0ppm of hydrogen sulfide was measured in the treated nitrogen gas. As canbe seen from these results, the activated zinc oxide demonstratedsuperior results, with the activated zinc oxide removing a greateramount of hydrogen sulfide than the non-activated zinc oxide.

[0062] Thus, there has been shown and described a novel method andcomposition for activating oxides reactant with sulfur compounds toremove sulfur compounds from fluids which fulfill all the objects andadvantages sought therefore. It is be apparent to those skilled in theart, however, that many changes, variation, modification, and other usesand applications for the subject method and composition are possible,and also such changes, variations, modifications, and other uses andapplications which do not depart from the spirit and scope of theinvention are deemed to be covered by the invention which is limitedonly by the claims which follow.

What is claimed is:
 1. A process for increasing the efficiency ofremoval of sulfur compounds from fluids, comprising passing the fluidsthrough an oxide product having a temperature equal to or less than 300°C. which is activated by an amount of activator, the oxide product isreactive with sulfur and is selected from the group consisting of ironoxide, zinc oxide, and combinations thereof, said activator is selectedfrom the group consisting of platinum oxide, gold oxide, silver oxide,copper oxide, copper metal, copper carbonate, copper alloy, cadmiumoxide, nickel oxide, palladium oxide, lead oxide, mercury oxide, tinoxide, and cobalt oxide, with said activator added to the oxide productin an amount equal to from about 0.125% by weight to about 5% by weightof the total composition, with said activator increasing the rate ofreactivity of the oxide product with the sulfur compounds found in thefluid so that the oxide product removes the sulfur from the fluids. 2.The process of claim 1, wherein said activator is added to the oxideproduct in a ratio equal to 1 part by weight of said activator to about10 to about 50 parts by weight of the oxide product.
 3. A process forincreasing the efficiency of removal of sulfur compounds from fluids,comprising passing the fluids through an oxide product activated by anamount of activator with the oxide product having a temperature equal toor less than 300° C., with the oxide product selected from the groupwith consisting of iron oxide, zinc oxide, and combinations thereof,said activator being a copper species and having a higherelectro-potential than the oxide product, with said activator increasingthe rate of reactivity of the oxide product with the sulfur compoundsfound in the fluid.
 4. The process of claim 3, wherein said copperspecies are selected from the group consisting of copper alloy, copperoxides, copper metal, copper carbonate, and combinations thereof.
 5. Theprocess of claim 3, wherein said activator is added to the oxide productin an amount equal to from about 0.125% by weight to about 5% by weightof the total composition.
 6. The process of claim 3, wherein saidactivator is added to the oxide product in a ratio equal to 1 part byweight of said activator to about 10 to about 50 parts by weight of theoxide product.
 7. A composition designed for scavenging sulfur compoundsin fluids, wherein said composition is comprised of an oxide product andan activator, with said oxide product selected from the group consistingof iron oxide, zinc oxide, and combinations thereof, said activatorequal to from about 0.125% to about 5% by weight of the oxide productactivator composition, said activator composition having a higherelectro-potential than the oxide product, with said activator being acopper species and increasing the reactivity of the oxide product withthe sulfur compounds.
 8. The composition designed for scavenging sulfurcompounds in fluids of claim 7, wherein said copper species are selectedfrom the group consisting of copper metal, copper alloy, copper oxide,copper carbonate, and combinations thereof.
 9. The composition designedfor scavenging sulfur compounds in fluids of claim 8, wherein saidcopper oxides are selected from the group consisting of cupric oxide andcuprous oxide.
 10. A composition for activating a pervious bed made ofcarriers and an iron oxide reactant, wherein said activation compositionis selected from the group consisting of noble metal oxides, noble metalalloys, and noble metals with said group having a higherelectro-potential than the iron oxide.
 11. A process for removinghydrogen sulfide from hydrocarbon fluids involving adding an activatorto an oxide, wherein said activator couples to the oxide to increase therate of reaction of the oxide with the sulfide, with said activatorhaving a higher electro-potential than the oxide.